Looking for new materials with Dirac points has been a fascinating subject of research. Here we report the growth, crystal structure, and band structure of HfGe0.92Te single crystals, featuring three different types of Dirac points. HfGe0.92Te crystalizes in a nonsymmorphic tetragonal space group P4/nmm (No. 129), having square Ge-atom plane with vacancies about 8%. Despite the vacancies on Ge site, the Dirac nodal line composed of conventional Dirac points vulnerable to spin-orbit coupling (SOC) is observed using angle-resolved photoemission spectroscopy, accompanied with the robust Dirac line protected by the nonsymmorphic symmetry against both SOC and vacancies. Specially, spin-orbit Dirac points (SDPs) originated from the surface formed under SOC are hinted to exist according to our experiments and calculations. Quasi-two-dimensional (quasi-2D) characters are observed and further confirmed by angular-resolved magnetoresistance. HfGe0.92Te is a good candidate to explore exotic topological phases or topological properties with three different types of Dirac points and a promising candidate to realize 2D SDPs.
@article{arxiv.2201.05833,
title = {Robust Dirac lines against Ge vacancy and possible spin-orbit Dirac points in nonsymmorphic HfGe0.92Te},
author = {L. Chen and L. Q. Zhou and Y. Zhou and C. Liu and Z. N. Guo and S. Y. Gao and W. H. Fan and J. F. Xu and Y. X. Guo and K and Liao and J. O. Wang and H. M. Weng and G. Wang},
journal= {arXiv preprint arXiv:2201.05833},
year = {2022}
}